<!DOCTYPE html>
<html>
<head>
  <title>Jquery</title>
  <script src="http://libs.baidu.com/jquery/1.9.0/jquery.js" type="text/javascript"></script>
  <link href="style.css" rel="stylesheet" type="text/css">
  <script type="text/javascript">
     function sayhello(){
       $("#test").show();
     }
  </script>
</head>
<body>
  <div id="test">hello jquery</div>
  <button id="btntest" onclick="sayhello()">common</button>
  <div id="divtest">divrr</div>
  <div id="default">hello</div>
  <div class="red">red</div>
  <div class="green">green</div>
</body>
<script type="text/javascript">
     $("#default").html($("#divtest").html());
     $("#btntest").attr("disabled","true");
     var $redHTML = $(".red").html();
     $(".green").html($redHTML)
</script>
</html>